Reflectors, designed to direct light from an omnidirectional source in a limited range of directions, are currently in existence. Search lights, stadium lights, car headlights and flashlights are examples. More recently such reflectors have been designed for light emitting diodes (LEDs), which are nearly perfect hemispherical (Lambertian) sources. These reflectors include collimating horns for LEDs, and these devices are inexpensive, easy to fabricate, have favorable optical characteristics and can use reflective films to great advantage. These horns have been used for a single LED and for an array of LEDs. The arrays of LEDs are packed together as close as possible to approximate a point source as best as possible. This configuration creates a problem with thermal management because the heat from the LEDs is concentrated and must be removed. Highly thermally conductive materials, large heat sinks, fans and liquid cooling have been used to remove the heat. Spreading the LEDs out over a larger area helps allows the heat to dissipate more readily but makes it more difficult to control the direction of the light with a single horn.